The following articles are treated in this paper : - 1. Introduction. 2. How are the "primary" weathering products chemically constituted? 3. Are the ferric silicates contained in the weathering products? 4. Are all the "clay complexes" in soils crystalline? 5. Is the "absorption compound theory" completely disproved? 6. The siliceous and less-siliceous clays, and the adventitious ingredients. 7. To what extent has the silica-sesquioxide ratio its significancy? 8. Are the acid treatments of soils to be completely rejected? 9. Supplements (the separation and chemical analysis of clay fraction, etc.) The materials are taken mainly from ROBINSON'S THE SOIL (1932) and partly from MARSHALL'S COLLOIDS IN AGRICULTURE (1935) with the writer's short critical and explanatory notes. The opinions of other authors are also referred at times. The writer remarks that the "crystalline clay theory" is not yet arrived at the position of disproving the older "absorption compound theory" completely, and that the silica-sesquioxide ratio can not adequately be a plied to the majority of our common soils, which are rich in the adventitious sesquioxides, especially in the ferric oxide. The writer is of opinion that the acid treatments of soils have the practical importance in most cases, if they are cautiously done and their results are judiciously interpreted. He, moreover, maintains that the methods of separation and chemical analysis of the "clay fraction" must fully be reexamined and justified, before they are adopted widely in this country.

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Experiments were conducted to prove that nitrification in soil is not entirely bacterial, but at least in part, due to photo-oxidation which takes place at the presence of various organic and inoganic photosensitizers under the influence of sunlight. The results will be summarized as follows ; - 1. There was observed no oxidation of ammonium-carbonate, kept in the dark or in the absence of photo-catalysts even when it was exposed to sunlight for 148 hours. 2. Ammonium-sulphate was also oxidized by ultra-violet ray from quartz mercury vapour lamp. 3. Comparative experiments showed the following order of photosensitizing activity of various compounds. ZnO>TiO_2,TiO_2 oxide gel>Ti(OH)_4+Aq>Animal charcoal, CaO>Na_2U_2O_7,K_2TiO_3,Fe_2O_3,MgO. 4. When aqueous solution of ammonium salt was kept distinetly alkaline by the addition of CaCO_3 or 10% NaOH or KOH solution throughout the exposure, the rate of oxidation was greatly increased. 5. Photosensitizing activity of TiO_2 and titanium oxide gel prepared after Graham's method was markedly altered by heating for 2 hours at various temperatures. In the case of TiO_2,the activity was increased by ignition at from 100° to 800℃. And in the case of titanium oxide gel, it was increased until 450℃. and showed a rapid fall at 800℃. 6. The effects of the amount of TiO_2,concentration of ammonium salt applied and the time of exposure upon the above photo-oxidation were tested and it was found that the photo-oxidation was increased with these amounts but without any proportionality. 7. The oxidation of ammonium-sulfate was also studies with quartz sand and soil heated 2 hours at 600℃. Ammonium-sulphate solution mixed with the heated soil or quartz sand with or without small quantity of TiO_2 and CaCO_3 was oxidized more in sunlight than in dark. Further, it was found that the photo-oxidation was increased markedly by the surface area of soil-particles.

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The results may be summarized as follows : - 1). In the first growing stage of rice-plant, inorganic manures i. e quick manure is very effective to its plant's growth but the plant too soft and weak. On the other hand, Organic manures i. e slow manure is slightly effective but very healthy. And there is characterisitc difference between organic and inorganic manures in respect with leaf colour of rice-plant, especially of its root colour. 2). Nitrogen content in rice tends to increase together increasing quantity of fertilised nitrogen. 3). Fertilised with organic manure, the amount of calcium absorption is very much than inorganic manure. 4) The animal and vegetable flakes are not suitable for "Waseasahi No. 2," but fermented manure is very effectively for "Aichiasahi" as their manure respectively. 5). The rices fertilised with fermented manure are very weighty on their one thousand graines and numberous on perfect grains. And then their shape and quality are very arrangement, but their lustre is slightly. 6). The rices fertilised with animal and vegetable flakes respectively contain many inperfect grarns comparatively. And then their quality are not good and their hardness is generally low. 7). The rices fertilised with (NH_4)_2SO_4 contain inperfect grains numberously and have bad quality. 8). The rices fertilised with CaCN_2 are weighty and contain perfect grains numberously. And then their lustre is brilliant but green-colour-rices are containd very much.

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An experiment was carried on for several years at the Saitama Agricultural Experiment Station to ascertain the comparative effects of the rice bran, which is applied very widely in the vegetable culture in this country, lime of superphosphate and farmyard manure on the yield and quality of the sweet potato (Convalvulus Batatas L.) and Welsh onion (Allium fistirosum L.). The experimental plots were taken as follows (N=sulphate of ammonia, K_2O=sulphate of potash) : [table]The results obtained are summarized as follows : 1. As to the yield in the sweet potato, the plots were put in the order as (6)>(4)>(3)>(2)>(5)>(1), and positive effects of phosphoric acid and farmyard manure were clearly observed. 2. In Welsh onion the plots came in the order accordding to their yields as (6)>(2)>(4)>(5)>(3)>(1), and here also marked effects of phosphoric acid and farmyard manure were seen. 3. The result of chemical analysis of the sweet potato showed that, in the plot of lime of superphosphate with farmyard mamure starch was increased, while in the plots of rice bran, both with and without farmyard manure, crude fibre was increased. No appreciable relation could be observed between the sugar contents of harvests and the kinds of manure applied. The addition of farmyard manure showed a tendency to increase starch contents of harvests. 4. In Welsh onion, sugar was increased in the plots of lime of superphosphate, both with and without farmyard manure. The crude fibre contents were high in the plot of lime of superphosphate, as well as in that of rice bran with farmyard manure. As a rule, the application of lime of superphosphate was liable to increase sugar contents of harvests, and the addition of farmyard manure gave the same effect besides it tended to increase crude fibre contents. 5. It may be regarded that it is one of very beneficial systems of manuring in the vegetable culture to apply lime of superphosphate and farmyard manure instead of rice bran, because the formers are cheeper in cost and yet promise better harvests in yield and quality than the latter.

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1. The analyses of the total P_2O_5 were made on the so-called susdensoid and emulsoid clays which were obtained from 50 uncultivated residual soils of various geological and petrographical origins. 2. For the determination of P_2O_5 in the suspensoid clay, the Na_2O_2 method was employed. In the case of the emulsoid clay, however, the conc. HCl method was nsed ; because, the latter method gave the same figures as resulted by the Na_2O_2 method. 3. The amount of P_2O_5 obtained, varied with the nature of the soil, ranging from 0.19 to 0.48% in the case of susbensoid clay, and 0.14 to 0.30% in the case of emulsoid clay. The average amounts, and mean and probable deviations are as follows : [table]4. Comparison of the emulsoid clays with the corresponding suspensoid clays shows a fairly marked diminution of total phosphoric acid. 5. Generally speaking, the soil colloids which were derived from the volcanic ashes and metamorphic rocks, show the presence of comparatively large amount of P_2O_5,whereas those of tertiary and mesozoic origins contain its relatively small quantity.

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To a highly acidic Soil^<(1)> with very low exchangeable lime content added CaCO_3 in ascending rates of amount and planted paddy rice. From the results of experiments the author could confirm that the paddy rice grows quite normally on the highly acidic Soil with very low exchangeable lime content, and also grows fairly good on the Soil which has good supply of lime and reacts basic. Namely, the range of reaction which adapt for the normal growth of paddy rice is very wide. (1) This Journal ; Vol. 9. No. 4. (1935)

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The chief results are here summarised as follows : - 1. The authors described about the formation and the properties of Mediterranean terra rossa according to the literature to compare with Manchurian terra rossa. 2. The author described about the climate, topography, geology, structure of profiles, weathering of dolomitic lime-stone and the productivity of the terra rossa of Kuantung-Chou, South Manchuria. 3. The climatic conditions of the region are as follows : -[table]According to the above results, the Lang's rainfactor and the Mayer's N-S quotient are a little higher than those of Mediterranean region, but it is almost same to have an important factor of alteration of wet and dry seasons. 4. The mother rocks of the region consist of various dolomitic lime-stone of upper archaean or under cambrian period and the terra rossa occurs only on the various dolomitic limestone, not on other rocks. 5. The upper horizon (A) of profiles consists of clay-loam, loam or sandy loam with gravels and iron concretion, but the under horizon (B) consists of clay and rich in mineral colloids. The characteristics of upper horizon are less humus and its dull yellowish brown color, which originated during the process of soil formation through the natural weathering. The characteristics of under horizon are its strong water holding capacity and its color (from red-brown to brownish red or purple red) and do not exhibit the acid reaction not with standing unsaturation soil to the alkaline bases. 6. Anothers characteristics of the soil are its low value of molecular ratios of SiO_2/Al_2O_3 and SiO_2/R_2O_3,dissolved in strong HCl (specific gravity 1.15). The calculated molecular ratios are described by the author as follows : -[table]These show an approximate ratios as those of Mediterranean terra rossa. 7. These soils stained indigo blue by methylene blue and light redish brown by acid fuchsin. These soils absorbed 4.1-4.9 c. gms. of methylene blue and 0.35-1.05 c. gms. of acid fuchsin per gram of soil. This fact explains that the soil contains both positive and negative colloids. The quantity of aluminium extracted by Dr. Seki's method (boiled for 5 minutes with 10% of Na_2CO_3 solution) are very much than silica and the value of its molecular ratio are 0.3-0.6,which correspond to about 1/4 of those of strong HCl extract. According to the results, the authors assume that the main part of colloids are consisted of colloidal clay and less quantity of free aluminium, because the amount of silica occuring in 10% Na_2CO_3 solution seems insufficient to hold as a silicate combination. 8. The value of SiO_2/Al_2O_3 and SiO_2/R_2O_3 ratios of the products of weathered dolomitic limestone, dissolved in strong HCl, are almost same as those of the soil. 9. The authors assumes that the structure of the profiles, physico-chemical properties and the mode of formation of the soil are almost same to those of Mediterranean terra rossa. From these reason, these Manchurian soils are called by tbe authors as terra rossa. 10. These soils are poor in content of available nutrients, and have very high absorption power of nitrogen and phosphorous. According to the results of culture experiments by the authors, these soils have strong requires of available nutrients, especialy in phosphorous and nitrogen. In this soil, one part of the fertilizer applied will be converted into unavailable form.

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1. Rice and barley plants grown in the fields contain very large amounts of silicic acid as the following analytical results show : [table]2. When the rice seed was unhulled before sowing, the seedlings grew very poorly in the culture solution, but their growth was so much improved that the seedlings appeared almost normal as the control plants by addition of a little amount of ground hulltissues or pure silicic acid in the culture solution. When the tolerable quantity of soil or sand was added in the culture solution, the unhulled seedlings grew almost normal. 3. The addition of colloidal silicic acid in the culture solution decreases the injury by cold for young barley plants. The silicic acid in the hull seemed, to some extent, to be useful as a nutrient for young barley.

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